We don't eat out often, but when we do, unless it's our local sushi joint, we always use a coupon. A great resource I've mentioned before is Restaurant.com You can purchase a $25 coupon for $10 at many different restaurants around the country. There are some stipulations (like gratuity included, specific total bill amount, etc.), so make sure and read the fine print before you purchase. The site also often has deals for 60% or more off - like right now if you use the code: FESTIVE you can get 60% off your order, so for only $4 you can purchase a $25 coupon.
We often use these when traveling. On a trip to Vegas this summer we picked up two for $8 total (a 60% off sale) and had two nice dinners for $20 and $14 (including the cost of the certificate).